Microvascular autonomic dysfunction may justify false-positive stress myocardial perfusion imaging in patients with liver cirrhosis undergoing liver transplantation

Cardiac imaging for the assessment of patients being evaluated for liver transplantation

Cardiac risk assessment prior to liver transplantation has become widely accepted. With the emergence of nonalcoholic steatohepatitis among the leading causes of end-stage liver disease and the steady rise of the age of liver transplant recipients, the burden of cardiovascular diseases has markedly increased in this population. Selecting appropriate liver transplant candidates is crucial due to the increasing demand for scarce donor organs. The use of noninvasive cardiac imaging for pre-operative assessment of the cardiovascular status of liver transplant recipients has been on the rise, yet the optimal assessment strategy remains an area of active debate. In this review, we examine the relevant literature pertaining to the diagnostic and prognostic applications of noninvasive cardiac imaging in this population. We also propose a simple literature-based evaluation algorithm for CAD surveillance in liver transplant candidates.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the past years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato, the Società Italiana di Diabetologia and the Società Italiana dell'Obesità reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure and Istituto Superiore di Sanità. Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources.Level of evidence Level of evidence of recommendations for each PICO question were reported according to available evidence.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes, and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the last years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato (AISF), the Società Italiana di Diabetologia (SID) and the Società Italiana dell'Obesità (SIO) reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure (CNEC) and Istituto Superiore di Sanità (ISS). Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources. Level of evidence: Level of evidence of recommendations for each PICO question were reported according to available evidence.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes, and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the last years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato (AISF), the Società Italiana di Diabetologia (SID) and the Società Italiana dell'Obesità (SIO) reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure (CNEC) and Istituto Superiore di Sanità (ISS). Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources. Level of evidence: Level of evidence of recommendations for each PICO question were reported according to available evidence.

Cardiac stress testing and coronary artery disease in liver transplantation candidates: Meta-analysis

AIM

To evaluate the diagnostic value of dobutamine stress echocardiography (DSE) and myocardial perfusion scintigraphy (MPS) in predicting coronary artery disease (CAD) in cirrhotic patients listed for liver transplantation (LT), using invasive coronary angiography (ICA) as gold-standard.

METHODS

Retrieval of studies was based on Medical Subject Headings and Health Sciences Descriptors, which were combined using Boolean operators. Searches were run on the electronic databases Scopus, Web of Science, EMBASE, MEDLINE (PubMed), BIREME (Biblioteca Regional de Medicina), LILACS (Latin American and Caribbean Health Sciences Literature), Cochrane Library for Systematic Reviews and Opengray.eu. There was no language or date of publication restrictions. The reference lists of the studies retrieved were searched manually.

RESULTS

The search strategy retrieved 322 references for DSE and 90 for MPS. In the final analysis, 10 references for DSE and 10 for MPS were included. Pooled sensitivity was 28% and 61% for DSE and MPS and specificity was 82% and 74%, for diagnosis of CAD using ICA as gold-standard, respectively.

CONCLUSION

DSE and MPS do not have adequate sensitivity for determination of whether CAD is present, despite having significant specificity.

Liver Transplantation in Patients With Cardiac Disease

Liver transplantation (LT) is a unique surgical procedure that has major hemodynamic and cardiovascular implications. Recently, there has been significant interest focused on cardiovascular issues that affect LT patients in all phases of the perioperative period. The preoperative cardiac evaluation is a major step in the selection of LT candidates. LT candidates are aging in concordance with the general population; cardiovascular disease and their risk factors are highly associated with older age. Underlying cardiovascular disease has the potential to affect outcomes in LT patients and has a major impact on candidate selection. The prolonged hemodynamic and metabolic instability during LT may contribute to adverse outcomes, especially in patients with underlying cardiovascular disease. Cardiovascular events are not unusual during LT; transplant anesthesiologists must be prepared for these events. Advanced cardiovascular monitoring techniques and treatment modalities are now routinely used during LT. Postoperative cardiovascular complications are common in both the early and late posttransplant periods. The impact of cardiac complications on posttransplant mortality is well recognized. Emerging knowledge regarding cardiovascular disease in LT patients and its impact on posttransplant outcomes will have an important role in guiding the future perioperative management of LT patients.

Incidence of and Risk Assessment for Adverse Cardiovascular Outcomes After Liver Transplantation: A Systematic Review

BACKGROUND

Cardiovascular events represent a major source of morbidity and mortality after liver transplantation and will likely increase given the aging population and nonalcoholic fatty liver disease as a leading indication for transplant. The optimal cardiovascular risk stratification approach in this evolving patient population remains unclear. The aims of this systematic review are to: (1) refine the definition, (2) characterize the incidence, and (3) identify risk factors for cardiovascular events post-liver transplantation. Additionally, we evaluated performance characteristics of different cardiac testing modalities.

METHODS

MEDLINE via PubMed, EMBASE, Web of Science, and Scopus were searched for studies published between 2002 and 2016 (model of end-stage liver disease era). Two authors independently reviewed articles to select eligible studies and performed data abstraction.

RESULTS

Twenty-nine studies representing 57 493 patients from 26 unique cohorts were included. Definitions of cardiovascular outcomes were highly inconsistent. Incidence rates were widely variable: 1% to 41% for outcomes of 6 months or shorter and 0% to 31% for outcomes longer than 6 months. Multivariate analyses demonstrated that older age and history of cardiac disease were the most consistent predictors of cardiovascular events posttransplant (significant in 8/23 and 7/22, studies, respectively). Predictive capacity of various cardiac imaging modalities was also discrepant.

CONCLUSIONS

The true incidence of cardiovascular outcomes post-liver transplant remains unknown in large part due to lack of consensus regarding outcome definition. Overall, poor data quality and gaps in knowledge limit the ability to clearly identify predictors of outcomes, but existing data support a more aggressive risk stratification protocol for patients of advanced age and/or with preexisting cardiac disease.

Perioperative Cardiovascular Evaluation for Orthotopic Liver Transplantation

Patients with advanced liver disease have a high prevalence of cardiovascular risk factors, but many of them are asymptomatic. Cardiovascular risk stratification prior to liver transplant can be done by dobutamine stress echocardiography, stress myocardial perfusion imaging, cardiac computer tomography, and coronary angiography, but there are no clear recommendations regarding what method should be used and who should be screened. Because of this and because of inherent risk profile in this population, the variations in practice are significant. Careful screening and rigorous management of cardiovascular risk factors are important to ensure optimal cardiovascular outcomes in the immediate post-transplantation period and in the long term as well.

Coronary multidetector computed tomographic angiography to evaluate coronary artery disease in liver transplant candidates: methods, feasibility and initial experience

AIMS

In patients undergoing orthotopic liver transplantation (OLT), coronary artery disease (CAD), obstructive and nonobstructive, is associated with high morbidity and mortality. In OLT candidates, stress testing for detecting ischemia is often inaccurate, and this patient population often has relative contraindications for cardiac catheterization. The objective of this study was to describe the methods, assess the feasibility and determine the extent and severity of CAD in OLT candidates without a prior history of CAD using coronary multidetector computer tomographic angiography (MDCTA).

METHODS

Sixty-five OLT candidates without known CAD underwent coronary MDCTA with dual source cardiac computed tomography (Siemens Definition). Coronary arteries were divided into 17 segments based on American Heart Association guidelines and evaluated independently by two blinded reviewers. Image quality of coronary MDCTA was assessed on a four-point Likert scale (0 = poor, 1 = fair, 2 = good, and 3 = excellent). Atherosclerotic lesions were evaluated for severity [mild (0-50%), moderate (51-70%), and severe (71-100%)], morphology, extent, location and consistency.

RESULTS

Image quality was graded as good or excellent in 73.8%. In this cohort of OLT candidates without known CAD, 9% had normal coronary arteries, 58% had mild CAD and 34% had moderate to severe CAD. Plaque severity and burden scores were high.

CONCLUSION

The prevalence of asymptomatic CAD is high in OLT candidates. Coronary MDCTA is feasible in OLT candidates and appears to be a useful technique to diagnose occult CAD in this patient population.

The heart in liver transplantation

The heart and liver are organs that are closely related in both health and disease. Patients who undergo liver transplantation may suffer from heart disease that is: (a) related to the original cause of the liver disease such as hemochromatosis, (b) related to the liver disease itself, or (c) related to other associated conditions. Furthermore, liver transplantation is one of the most cardiovascular stressful events that a patient with cirrhosis may undergo. After liver transplantation, the progression of pre-existing or the development of new-onset cardiac disease may occur. This article reviews the relationship between the heart and liver transplantation in the pre-transplant, intra-operative, and post-transplant periods.

Clinical value of myocardial perfusion scintigraphy as a screening tool in liver transplant candidates

A cardiac evaluation before orthotopic liver transplantation (OLT) is imperative. Previous investigations have demonstrated that mild to moderate reversible perfusion defects on myocardial perfusion scintigraphy (MPS) in general are associated with a low risk for perioperative cardiac events. The objective of this study was to assess any perfusion defects in consecutive patients with chronic liver disease who were undergoing OLT. OLT candidates underwent extensive cardiovascular screening that included, among other methods, MPS. Patients who had no contraindications for surgery and underwent OLT were followed up. The occurrence and risk of complications and mortality were compared in 3 groups of patients: patients with normal MPS results, patients with any reversible defect, and patients with a fixed perfusion defect on MPS. In all, 156 subsequent patients underwent OLT. One or more reversible segmental perfusion defects on MPS were present in 14 patients (<3 segments, n = 12; 3 segments without obstructive coronary artery disease, n = 2). The risk of complications did not differ significantly between patients with normal MPS findings and patients with a reversible perfusion defect (odds ratio = 3.04, 95% confidence interval = 0.65-14.26, P = 0.16), although the study was not sufficiently powered to show a difference. The presence of 1 or more reversible defects on MPS was significantly associated with an increased incidence of all-cause 1-year mortality (hazard ratio = 3.17, 95% confidence interval = 1.02-9.83, P = 0.046). No significant difference in the outcomes of patients with normal MPS findings and patients with a fixed defect on MPS was found; the study was, however, not adequately powered to do so. In conclusion, the results of this small cohort study indicate that patients with mild to moderate reversible perfusion defects on MPS may have inferior survival characteristics in comparison with patients with normal MPS results. A prospective, adequately powered study is required to confirm the results of this study.

The heart and the liver

Cardiac failure affects the liver and liver dysfunction affects the heart. Chronic and acute heart failure can lead to cardiac cirrhosis and cardiogenic ischemic hepatitis. These conditions may impair liver function and treatment should be directed towards the primary heart disease and seek to secure perfusion of vital organs. In patients with advanced cirrhosis, physical and/or pharmacological stress may reveal a reduced cardiac performance with systolic and diastolic dysfunction and electrophysical abnormalities, termed cirrhotic cardiomyopathy. Pathophysiological mechanisms include reduced beta-adrenergic receptor signal transduction and defective cardiac electromechanical coupling. However, the QT interval is prolonged in approximately half of patients with cirrhosis and it may be improved by beta-blockers. No specific therapy can be recommended but it should be supportive and directed against the heart failure. Transjugular intrahepatic portosystemic shunt insertion and liver transplantation affect cardiac function in portal hypertensive patients and cause stress to the cirrhotic heart, with a risk of perioperative heart failure. The risk and prevalence of coronary artery disease are increasing in cirrhotic patients and since perioperative mortality is high, careful evaluation of such patients with dobutamine stress echocardiography, coronary angiography and myocardial perfusion imaging is required prior to liver transplantation. Future research should focus on beneficial effects of treatment on cardiac function and mortality.